Step 1

Place the oil in a medium saucepan over medium heat. Then add shallots into the pan, no need to wait for the oil to warm up. Cook the shallots, gently stirring often, for about 15-20 minutes. If you notice the shallots browning too quickly, lower the heat, as needed until the shallots achieve a golden-brown color.

Step 2

Use a fish spatula (or similar utensil) to remove the crisp shallots and place onto a paper towel-lined plate to blot excess oil. Season crispy shallots with cajun seasoning or seasoned salt- to taste. Set aside until green bean casserole is ready to assemble. Then place a fine-meshed sieve over a bowl to remove any shallot debris and save shallot-infused oil for future use!

Step 3

Preheat the oven to 375°F.

Step 4

Bring a large pot of water to a boil. Once boiling, add in the green beans and cook for 3 minutes. Drain immediately and place green beans into a bowl filled with cold water and ice to stop the cooking process. Once cool, drain the green beans and set aside.

Step 5

In a large skillet over medium heat, add the butter. Once melted, add the mushrooms and garlic and sauté until the mushrooms are tender and lightly golden, about 3-4 minutes.

Step 6

Next, add the flour and stir until well combined and the flour has mostly dissipated. Slowly pour in the chicken broth and stir well to combine, be sure to hit any hidden pockets of flour. Use a wooden utensil to scrape up any browned bits on the bottom of the pan.

Step 7

Stir in the lemon juice, dijon mustard, worcestershire, thyme, red pepper flakes (if using), ground nutmeg, and salt/pepper- to taste, stirring well to fully combine. Bring this mixture to a simmer for 2-3 minutes.

Step 8

Then stir in the cream (or half and half) along with half of the parmesan, stirring until well incorporated, about 1-2 minutes.

Step 9

Place the blanched green beans into an oven-safe casserole dish and pour the creamy mushroom sauce on top and toss until well coated. Evenly sprinkle the remaining parmesan over the green bean mixture.

Step 10

Transfer the dish into the oven and bake for 20 minutes.

Step 11

Then remove from the oven and toss the mixture once more. Evenly sprinkle the fried shallots over the green beans. Place back into the oven to bake for another 7-10 minutes, careful not to burn.

Step 12

Serve this green bean casserole immediately. Enjoy!